Key unit and keyboard using the same

ABSTRACT

A key unit and a keyboard using the same are provided. The key unit includes a circuit board, a supporting assembly, a keycap, and a floating conductive structure. The circuit board includes a capacitance sensing circuit embedded therein, and the capacitance sensing circuit includes a pair of sensor electrodes which are spaced apart from each other. The supporting assembly is disposed on the circuit board. The keycap is moveably disposed above and spaced apart from the circuit board. The supporting assembly disposed between the keycap and the circuit board allows the keycap to be moved between a non-depressed position and a depressed position with respect to the circuit board. The floating conductive structure is disposed on the supporting assembly, and an orthogonal projection of the floating conductive structure on the circuit board overlaps with the pair of sensor electrodes.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of U.S. application Ser. No.16/843,570, filed on Apr. 8, 2020 and entitled “KEY UNIT AND KEYBOARDUSING THE SAME,” the entire disclosures of which are incorporated hereinby reference.

FIELD OF THE DISCLOSURE

The present disclosure relates to an input unit and a keyboard using thesame, and more particularly to a key unit and a keyboard using the same.

BACKGROUND OF THE DISCLOSURE

Keyboards are widely used in a computer system to serve as a userinterface so that a user can operate the computer system. One of themost common keyboard types is a “dome-switch” keyboard.

When a key is depressed, the keycap of the key pushes a rubber domedisposed beneath the keycap. The rubber dome is compressed and a tactilefeedback is given to the user pressing the key. At the same time, thedeformation of the rubber dome forces a conductive membrane disposedbelow the rubber dome to deform and be in contact with a pair ofconductive traces on the printed circuit board (PCB), thereby closing aswitch corresponding to the key.

A chip in the keyboard emits a scanning signal along each pair ofconductive traces on the PCB to all the keys. When the signalcorresponding to one of the pairs of conductive traces changes due tothe contact of the conductive membrane, the chip generates a codecorresponding to the key connected to that pair of conductive traces andthen transmits the code to a processor of a computer, so that theprocessor can generate a command corresponding to the key that isdepressed.

However, the key has to be depressed for a certain distance so as totrigger the switch corresponding to the key. Furthermore, when two ormore keys, such as an “A” key, a “W” key, and a “Q” key of the keyboardare depressed at the same time, it is likely for the chip to erroneouslyjudge that a signal corresponds to another key, such as an “S” key, thatis not depressed, which results in “phantom switch” problems.

SUMMARY OF THE DISCLOSURE

In response to the above-referenced technical inadequacies, the presentdisclosure provides a key unit and a keyboard using the same.

In one aspect, the present disclosure provides a key unit including acircuit board, a supporting assembly, a keycap, and a floatingconductive structure. The circuit board includes a capacitance sensingcircuit embedded therein. The supporting assembly is disposed on thecircuit board. The keycap is moveably disposed above and spaced apartfrom the circuit board. The supporting assembly disposed between thekeycap and the circuit board allows the keycap to be moved between anon-depressed position and a depressed position with respect to thecircuit board. The floating conductive structure is disposed on thesupporting assembly, and an orthogonal projection of the floatingconductive structure on the circuit board overlaps with the capacitancesensing circuit.

In certain embodiments, the capacitance sensing circuit includes a pairof sensor electrodes which are spaced apart from each other, and theorthogonal projection of the floating conductive structure on thecircuit board overlaps with the pair of sensor electrodes.

In certain embodiments, the supporting assembly includes a firstsupporting frame and a second supporting frame, and the floatingconductive layer is a conductive layer covering at least one of thefirst supporting frame and the second supporting frame.

In certain embodiments, the supporting assembly includes a firstsupporting frame and a second supporting frame, and the floatingconductive structure is a conductive layer that covers an upper part ofat least one of the first supporting frame and the second supportingframe.

In certain embodiments, the supporting assembly includes a firstsupporting frame and a second supporting frame, and the floatingconductive structure includes a first conductive layer and a secondconductive layer. The first conductive layer partially covers the firstsupporting frame, and the first conductive layer is located at an upperpart of the first supporting frame. The second conductive layerpartially covers the second supporting frame, and the second conductivelayer is located at an upper part of the second supporting frame. Theorthogonal projections of the first conductive layer and the secondconductive layer on the circuit board do not overlap with each other.

In certain embodiments, the key unit further includes a processingcircuit electrically connected to the pair of sensor electrodes toobtain a variation of a coupling capacitance between the pair of sensorelectrodes and to determine whether the keycap is touched or depressedaccording to a variation of coupling capacitance. In response to thevariation of the coupling capacitance is greater than a first thresholdvalue and less than a second threshold value, the keycap is determinedto be touched. In response to the variation of the coupling capacitanceis greater than the second threshold value, the keycap is determined tobe depressed.

In certain embodiments, the present disclosure provides a key unit, inthe key unit further includes an elastic element disposed on the circuitboard. The elastic element includes a connection portion and aprotrusion portion. The connection portion connects to the keycap, andthe protrusion portion extends from the connection portion toward thecircuit board. When the keycap is in a non-depressed position, theprotrusion portion is spaced apart from the circuit board.

In certain embodiments, the present disclosure provides a key unit, inwhich the circuit board has an opening that extends from an uppersurface of the circuit board to a position between the pair of thesensor electrodes and is in alignment with the protrusion portion. Whenthe keycap moves toward the circuit board, the protrusion portion ispushed into the opening without being in contact with the pair of thesensor electrodes.

In certain embodiments, the present disclosure provides a key unit, inwhich the circuit board includes a switch sensing circuit having atleast a contact point that is in alignment with the protrusion portion.The capacitance sensing circuit is disposed above and insulated from theswitch sensing circuit, and the circuit board has an opening inalignment with the contact point. The opening passes through thecapacitance sensing circuit, and does not pass through the switchsensing circuit.

In certain embodiments, the present disclosure provides a key unitfurther including a flexible conductive film disposed above andinsulated from the capacitance sensing circuit. The flexible conductivefilm covers the opening. When the keycap moves toward the circuit board,the protrusion portion forces the flexible conductive film to deform sothat the flexible conductive film extends into the opening to contactthe contact point below.

In one aspect, the present disclosure provides a key unit including acircuit board, a supporting assembly, a keycap, and a balance frame. Thecircuit board includes a capacitance sensing circuit embedded therein.The supporting assembly is disposed on the circuit board. The keycap ismoveably disposed above and spaced apart from the circuit board, and thesupporting assembly is disposed between the keycap and the circuit boardand allows the keycap to be moved between a non-depressed position and adepressed position with respect to the circuit board. The balance frameis disposed between the keycap and circuit board and surrounding thesupporting assembly. A least one of the balance frame and the supportingassembly is made of conductive material and has an orthogonal projectionon the circuit board overlapping with the pair of sensor electrodes.

In certain embodiments, the capacitance sensing circuit includes a pairof sensor electrodes which are spaced apart from each other, and theorthogonal projection of the balance frame on the circuit board overlapswith the pair of the sensor electrodes.

In one aspect, the present disclosure provides a keyboard including aplurality of key units and a processing circuit, and each of the keyunits includes a circuit board, a supporting assembly, a keycap, and afloating conductive structure. The circuit board includes a capacitancesensing circuit embedded therein. The supporting assembly is disposed onthe circuit board. The keycap is moveably disposed above and spacedapart from the circuit board. The supporting assembly disposed betweenthe keycap and the circuit board allows the keycap to be moved between anon-depressed position and a depressed position with respect to thecircuit board. The floating conductive structure is disposed on thesupporting assembly, and an orthogonal projection of the floatingconductive structure on the circuit board overlaps with the capacitancesensing circuit. The processing circuit is electrically connected to thecapacitance sensing circuit of each of the key units to obtain avariation of a coupling capacitance between the pair of sensorelectrodes and to determine whether the keycap is touched or depressedaccording to the variation of coupling capacitance. When the variationof the coupling capacitance is greater than a first threshold value andless than a second threshold value, the keycap is determined to betouched. When the variation of the coupling capacitance is greater thanthe second threshold value, the keycap is determined to be depressed.

In certain embodiments, the present disclosure provides a keyboardfurther includes a processor electrically connected to the processingcircuit. The processor determines whether a series of key units aretouched or pressed continuously in a predetermined sequence according tothe variations of the coupling capacitance respectively correspondingthereto.

In certain embodiments, the present disclosure provides a keyboardincludes a processor electrically connected to the key units and amemory electrically connected to the processor. The memory stores afirst program corresponding to a first gesture, and the processordetermines whether a gesture performed by a user is the first gesture ornot. The first gesture is touching a number of key units to form aparticular trace while pressing and holding down on another one of thekey units.

Therefore, one of the advantages of the present disclosure is that inthe key unit and the keyboard using the same provided herein, by thetechnical features of the floating conductive structure being disposedon the supporting assembly, in which an orthogonal projection of thefloating conductive structure on the circuit board overlaps with thecapacitance sensing circuit, or at least one of the balance frame andthe supporting assembly being made of conductive material and having anorthogonal projection on the circuit board that overlaps with thecapacitance sensing circuit, the accuracy of detection can be improvedand the “phantom switch” problems can be prevented even if more than twokey units of the keyboard are depressed at the same time.

These and other aspects of the present disclosure will become apparentfrom the following description of the embodiment taken in conjunctionwith the following drawings and their captions, although variations andmodifications therein may be affected without departing from the spiritand scope of the novel concepts of the disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure will become more fully understood from thefollowing detailed description and accompanying drawings.

FIG. 1 is a schematic sectional view of a key unit in an undepressedstate according to a first embodiment of the present disclosure.

FIG. 2 is a schematic sectional view of the key unit held in a depressedstate according to the first embodiment of the present disclosure.

FIG. 3 is a schematic sectional view of a key unit in an undepressedstate according to a second embodiment of the present disclosure.

FIG. 4 is a schematic sectional view of a key unit in an undepressedstate according to a third embodiment of the present disclosure.

FIG. 5 is a schematic sectional view of a key unit in an undepressedstate according to a fourth embodiment of the present disclosure.

FIG. 6 is a schematic sectional view of the key unit held by a finger inthe depressed state according to the fourth embodiment of the presentdisclosure.

FIG. 7 is a schematic sectional view of the key unit held by aninsulator object in the depressed state according to the fourthembodiment of the present disclosure.

FIG. 8 is a schematic sectional view of a key unit in an undepressedstate according to a fifth embodiment of the present disclosure.

FIG. 9 is a schematic sectional view of the key unit held in a depressedstate according to the fifth embodiment of the present disclosure.

FIG. 10 is a schematic sectional view of a key unit in an undepressedstate according to a sixth embodiment of the present disclosure.

FIG. 11 is a schematic sectional view of a key unit in an undepressedstate according to a seventh embodiment of the present disclosure.

FIG. 12 is a schematic sectional view of a key unit in an undepressedstate according to an eighth embodiment of the present disclosure.

FIG. 13 is a schematic sectional view of a key unit in an undepressedstate according to a ninth embodiment of the present disclosure.

FIG. 14 is a schematic sectional view of the key unit held by a fingerin the depressed state according to the ninth embodiment of the presentdisclosure.

FIG. 15 is a schematic sectional view of a key unit in an undepressedstate according to a tenth embodiment of the present disclosure.

FIG. 16 is a schematic sectional view of the key unit held by a fingerin the depressed state according to the tenth embodiment of the presentdisclosure.

FIG. 17 is a schematic sectional view of a key unit in an undepressedstate according to an eleventh embodiment of the present disclosure.

FIG. 18 is a schematic sectional view of the key unit located at amiddle position according to the eleventh embodiment of the presentdisclosure.

FIG. 19 is a schematic sectional view of the key unit held in thedepressed state according to the eleventh embodiment of the presentdisclosure.

FIG. 20 is a schematic sectional view of a key unit in an undepressedstate according to a twelfth embodiment of the present disclosure.

FIG. 21 is a schematic sectional view of the key unit held in thedepressed state according to the twelfth embodiment of the presentdisclosure.

FIG. 22 is a schematic sectional view of a key unit in an undepressedstate according to a thirteenth embodiment of the present disclosure.

FIG. 23 is a schematic sectional view of the key unit held in thedepressed state according to the thirteenth embodiment of the presentdisclosure.

FIG. 24 is a schematic sectional view of a key unit in an undepressedstate according to a fourteenth embodiment of the present disclosure.

FIG. 25 is a schematic sectional view of the key unit held in thedepressed state according to the fourteenth embodiment of the presentdisclosure.

FIG. 26 is a schematic sectional view of a key unit in an undepressedstate according to a twelfth embodiment of the present disclosure.

FIG. 27 is a top view of a keyboard according to an embodiment of thepresent disclosure.

FIG. 28 is a block diagram of a keyboard according to an embodiment ofthe present disclosure.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

The present disclosure is more particularly described in the followingexamples that are intended as illustrative only since numerousmodifications and variations therein will be apparent to those skilledin the art. Like numbers in the drawings indicate like componentsthroughout the views. As used in the description herein and throughoutthe claims that follow, unless the context clearly dictates otherwise,the meaning of “a”, “an”, and “the” includes plural reference, and themeaning of “in” includes “in” and “on”. Titles or subtitles can be usedherein for the convenience of a reader, which shall have no influence onthe scope of the present disclosure.

The terms used herein generally have their ordinary meanings in the art.In the case of conflict, the present document, including any definitionsgiven herein, will prevail. The same thing can be expressed in more thanone way. Alternative language and synonyms can be used for any term(s)discussed herein, and no special significance is to be placed uponwhether a term is elaborated or discussed herein. A recital of one ormore synonyms does not exclude the use of other synonyms. The use ofexamples anywhere in this specification including examples of any termsis illustrative only, and in no way limits the scope and meaning of thepresent disclosure or of any exemplified term. Likewise, the presentdisclosure is not limited to various embodiments given herein. Numberingterms such as “first”, “second” or “third” can be used to describevarious components, signals or the like, which are for distinguishingone component/signal from another one only, and are not intended to, norshould be construed to impose any substantive limitations on thecomponents, signals or the like.

First Embodiment

Reference is made to FIG. 1 and FIG. 2, which are schematic sectionalviews of a key unit respectively in an undepressed state and a depressedstate according to a first embodiment of the present disclosure.

It should be noted that only a portion of the keyboard is illustrated inFIG. 1 and FIG. 2 to describe the details of the key unit in the presentdisclosure. The key unit 1A provided in the present disclosure can beimplemented in any keyboard that is electrically connected to a personalcomputer or integrated within the housing or chassis of other devicecomponents.

In the instant embodiment, the key unit 1A includes a circuit board 10,an elastic element 11 and a keycap 12. One keyboard could include aplurality of key units 1A and each of the key units 1A represents acorresponding character or command. A processing circuit 13 isincorporated in the keyboard and couple to the plurality of key units1A.

As shown in FIG. 1, the circuit board 10 at least includes a capacitancesensing circuit 100 embedded therein for obtaining a variation of acapacitance. Specifically, the capacitance sensing circuit 100 includesa pair of sensor electrodes, such as a first sensor electrode 100 a anda second sensor electrode 100 b. It should be noted that each pair ofthe first sensor electrode 100 a and the second sensor electrode 100 bare insulated from each other so as to form an effective capacitor ateach sensing location.

When a bias is applied to the first sensor electrode 100 a or the secondsensor electrode 100 b, an electric field can be created between thefirst and second sensor electrodes 100 a, 100 b. Accordingly, an objectnear the pair of the first and second sensor electrodes 100 a, 100 bwould cause the electric field to be varied, thereby varying thecoupling capacitance between the first sensor electrode 100 a and thesecond sensor electrode 100 b. As such, by detecting the couplingcapacitance between the pair of the first and second sensor electrodes100 a, 100 b, a state of the key unit 1A can be determined.

In the instant embodiment, the circuit board 10 includes an insulatinglayer 101, and the capacitance sensing circuit 100 is formed on theinsulating layer 101. Furthermore, the circuit board 10 further includesat least one membrane 102 (more than one of which are illustrated inFIG. 1 and FIG. 2), and the membrane 102 is disposed on and covers thecapacitance sensing circuit 100 so as to prevent the capacitance sensingcircuit 100 from being damaged.

As shown in FIG. 1, the elastic element 11 is disposed on the circuitboard 10. In one embodiment, the elastic element 11 is compressible andresilient. The elastic element 11 is connected between the circuit board10 and the keycap 12, such that the keycap 12 can be moveably disposedon the circuit board 10. That is to say, the keycap 12 can moves betweena non-depressed position and a depressed position with respect to thecircuit board 10.

Specifically, in the instant embodiment, the elastic element 11 includesa connection portion 110, a protrusion portion 111, and a supportingportion 112. The connection portion 110 and the supporting portion 112are respectively connected to the keycap 12 and the circuit board 10. Assuch, when the key unit 1A is in the undepressed state (i.e., the keycap12 is located at the non-depressed position), the keycap 12 can bedisposed above the circuit board 10 without being contact with thecircuit board 10.

Furthermore, in the instant embodiment, the protrusion portion 111extends from the connection portion 110 toward the circuit board 10.However, when the key unit 1A is in the undepressed state, theprotrusion portion 111 is spaced apart from the circuit board 10, asshown in FIG. 1. That is to say, a gap exists between the protrusionportion 111 and the circuit board 10 before the keycap 12 is depressed.

It should be noted that as long as the keycap 12 can be maintained at acertain level relative to the circuit board 10, the structure of theelastic element 11 is not limited to the example provided herein. Forexample, the elastic element 11 can be a rubber dome or a metallic dome.

When the key unit 1A is pressed by a user with an object F, such as afinger, and held in the depressed state, the supporting portion 112 ofthe elastic element 11 is bent due to the applied pressure, and theprotrusion portion 111 is forced to be compressed and in contact withthe circuit board 10, as shown in FIG. 2.

In one embodiment, the key unit 1A further includes a supportingstructure (not shown in FIG. 1) disposed between the keycap 12 and thecircuit board 10. In one embodiment, the supporting structure is ascissors-shaped frame, and the elastic element 11 is disposed in thescissors-shaped frame. As such, the direction of movement of the keycap12 can be limited to a thickness direction of the circuit board 10.However, the present disclosure is not limited thereto.

As mentioned above, the keycap 12 is moveably disposed above and spacedapart from the circuit board 1. The keycap 12 has an outer surface 12 aand an inner surface 12 b. Furthermore, the keycap 12 can be made of,but not limited to, a conductive material, an insulting material or acomposite material. For example, the keycap 12 can be a metal-platedplastic keycap.

Furthermore, in one embodiment, the user can input a command through notonly pressing, but also through touching the key unit 1A. Specifically,the outer surface 12 a of the keycap 12 can serve as a touch sensitivesurface.

As shown in FIG. 1, when a user touches the outer surface 12 a of thekeycap 12 with an object F, such as a finger or a conductive object, anddoes not press the keycap 12, the electric field between the pair of thefirst and second sensor electrodes 100 a, 100 b are altered, thuschanging the coupling capacitance between the pair of the first andsecond sensor electrodes 100 a, 100 b.

In the instant embodiment, when the keycap 12 is pressed by the userwith the object F, as shown in FIG. 1 and FIG. 2, the closer the keycap12 is to the capacitance sensing circuit 100, the greater the variationof the electric field caused by the object F. Accordingly, compared to asituation where the keycap 12 is located at the non-depressed position,the coupling capacitance between the pair of the first and second sensorelectrodes 100 a, 100 b would become greater.

However, in another embodiment, the coupling capacitance may becomelower during the depression process of the keycap 12. Accordingly, inthe present disclosure, according to a variation of the couplingcapacitance, the state of the key unit 1A can be determined. It shouldbe noted that in different embodiments, the variation of the couplingcapacitance may be positive or negative during the depression of thekeycap 12, which may be dependent on the dielectric coefficient of theelastic element 11 or the material of the keycap 12. Accordingly,whether the coupling capacitance is positively or negatively varied witha depressing motion of the keycap 12 can be adjusted according tospecific requirements.

As shown in FIG. 1 and FIG. 2, the processing circuit 13 is electricallyconnected to the pair of the first and second sensor electrodes 100 a,100 b to detect the coupling capacitance between the pair of the firstand second sensor electrodes 100 a, 100 b and to determine whether thekeycap 12 is touched or depressed according to the coupling capacitance.

Specifically, the capacitance sensing circuit 100 can transmit acoupling capacitance signal, such as a current value or a voltage value,to the processing circuit 13, so that the processing circuit 13 canmeasure the variation of the coupling capacitance and determine whetherthe variation of the coupling capacitance is greater than a firstthreshold value or not. When the variation of the coupling capacitanceis greater than a first threshold value, the keycap 12 is determined tobe touched.

Furthermore, the processing circuit 13 can determine whether the keycap12 is depressed beyond a predetermined position or not according to thevariation of the coupling capacitance. To be more specific, theprocessing circuit 13 determines whether the variation of the couplingcapacitance is greater than a second threshold value or not. When thevariation of the coupling capacitance is greater than the secondthreshold value, the keycap is determined to be depressed beyond thepredetermined position.

In one embodiment, the absolute value of the second threshold is largerthan the absolute value of the first threshold. That is to say, thevariation of the coupling capacitance would reach the first thresholdvalue when the keycap 12 is touched, and then reach the second thresholdvalue when the keycap 12 is depressed gradually.

Second Embodiment

Reference is made to FIG. 3, which is a schematic sectional view of akey unit in an undepressed state according to a second embodiment of thepresent disclosure. The elements which are similar to or the same asthose shown in FIG. 1 are denoted by similar or the same referencenumerals, and will not be reiterated herein.

The key unit 1B further includes a floating conductive structure 14. Theconductive structure 14 can be disposed between the keycap 12 and thecircuit board 10 or disposed on the outer surface 12 a of the keycap 12.In the second embodiment, the floating conductive structure 14 is aconductive layer that is disposed on the outer surface 12 a of thekeycap 12.

When the keycap 12 is depressed, the floating conductive structure 14becomes closer to the capacitance sensing circuit 100 so that theelectric field between the pair of the first and second sensorelectrodes 100 a, 100 b is altered, thereby changing the couplingcapacitance. That is to say, the floating conductive structure 14 moveswith a motion of the keycap 12, such that the coupling capacitance isvaried. It should be noted that by disposing the floating conductivestructure 14, the electric field between the pair of the first andsecond sensor electrodes 100 a, 100 b is still altered even though thekeycap 12 is depressed by a nonconductive object (such as a plasticstylus).

It should be noted that the floating conductive structure 14 is notlimited to the example provided herein. In another embodiment, thefloating conductive structure 14 can be disposed on at least one of theinner surface 12 b and the outer surface 12 a of the keycap 12. That is,the floating conductive structure 14 can be disposed on only the innersurface 12 b of the keycap 12, or includes an inner conductive layer andan outer conductive layer which are respectively disposed on the innerand outer surfaces 12 b, 12 a of the keycap 12.

In yet another embodiment, the keycap 12 can be made completely of aconductive material to serve as the floating conductive structure.

Third Embodiment

Reference is made to FIG. 4, which is a schematic sectional view of akey unit in an undepressed state according to a third embodiment of thepresent disclosure. The elements which are similar to or the same asthose shown in FIG. 3 are denoted by similar or the same referencenumerals, and will not be reiterated herein.

In the third embodiment, the floating conductive structure 14 of the keyunit 1C is disposed between the keycap 12 and the circuit board 10. Thefloating conductive structure 14 is formed at the surface of the elasticelement 11. Specifically, in the instant embodiment, the floatingconductive structure 14 is also a conductive layer that is disposed onan end of the protrusion portion 111. However, the conductive layer canbe formed on another portion of the elastic element 11, and the presentdisclosure is not limited.

Furthermore, the floating conductive structure 14 can include more thanone conductive layer, such as two conductive layers, which arerespectively disposed on different elements.

Fourth Embodiment

Reference is made to FIG. 5, which is FIG. 5 is a schematic sectionalview of a key unit in an undepressed state according to a fourthembodiment of the present disclosure.

In the fourth embodiment, the floating conductive structure 14 includesa first conductive layer 14 a and a second conductive layer 14 b, whichare separate from each other. In the instant embodiment, both the firstconductive layer 14 a and the second conductive layer 14 b are disposedbetween the keycap 12 and the circuit board 10. The first conductivelayer 14 a is disposed on an end of the protrusion portion 111 of theelastic element 11, and the second conductive layer 14 b is disposed onthe inner surface 12 b of the keycap 12.

Furthermore, the second conductive layer 14 b covers only a partialregion of the inner surface 12 b of the keycap 12. To be more specific,the second conductive 14 b is disposed between the inner surface 12 b ofthe keycap 12 and the connection portion 110 of the elastic element 11.

Reference is made to FIG. 5 and FIG. 6, in which FIG. 6 is a schematicsectional view of the key unit held by a finger in the depressed stateaccording to the fourth embodiment of the present disclosure.

For the key unit 1D of the fourth embodiment, when the outer surface 12a of the keycap 12 is touched by the finger F of the user without beingapplied with any pressure, i.e., the keycap 12 is touched but notpressed, some charges would be attracted to the finger F and thenconducted to the ground. As such, the coupling capacitance between thepair of the first and second sensor electrodes 100 a, 100 b would becomeslightly lower.

In one embodiment, the processing circuit 13 can determine whether thekeycap 12 is touched by the user according to the variation of thecoupling capacitance. As mentioned previously, when the variation of thecoupling capacitance is greater than the first threshold value and lessthan a second threshold value, the processing circuit 13 determines thatthe keycap 12 is touched.

As shown in FIG. 6, the keycap 12 is pressed by the user with thefinger. It should be noted that although some charges are attracted tothe finger F, the floating conductive structure 14 that includes thefirst and second conductive layers 14 a, 14 b becomes closer to the pairof the first and second sensor electrodes 100 a, 100 b during thedepression of the keycap 12, which would cause the coupling capacitanceto be greater. That is to say, when the keycap 12 is depressed, whetherthe variation of the coupling capacitance is positive or negative may bedependent on combined effects resulting from the finger F and thefloating conductive structure 14.

In one embodiment, the position and the occupied area of the floatingconductive structure 14 can be designed so that the floating conductivestructure 14 can generate an effect on the variation of the couplingcapacitance that is more comprehensive than that generated by the fingerF. However, the present is not limited to the example provided herein.

Reference is made to FIG. 7, which is a schematic sectional view of thekey unit held by an insulator object in the depressed state according tothe fourth embodiment of the present disclosure. When the keycap 12 ofthe key unit 1D is pressed by a user with an insulator object F′, onlythe effects of the floating conductive structure 14 is considered. Thatis to say, the coupling capacitance would become greater during thedepression of the keycap 12 since the floating conductive structure 14becomes closer to the capacitance sensing circuit 100. Accordingly, thevariation of the coupling capacitance is positive.

Fifth Embodiment

Reference is made to FIG. 8 and FIG. 9, which are schematic sectionalviews of a key unit respectively in an undepressed state and in adepressed state according to a fifth embodiment of the presentdisclosure. The elements which are similar to or the same as those shownin FIG. 5 are denoted by similar or the same reference numerals, andwill not be reiterated herein.

In the fifth embodiment, the circuit board 10 of the key unit 1E furtherincludes a ground layer 103 disposed below the capacitance sendingcircuit 100. Furthermore, the ground layer 103 is insulated from thecapacitance sensing circuit 100. The ground layer 103 can be made of aconductive material, such as aluminum, steel or copper.

It should be noted that when the keycap 12 is depressed, the groundlayer 103 would provide more discharging paths of the charges in theeffective capacitor, thereby reducing the coupling capacitance. In theinstant embodiment, the effect of the ground layer 103 on the couplingcapacitance is bigger than those of the floating conductive structure 14and the material of the object F. That is, no matter whether the objectF for pressing the keycap 12 is conductive or not, the couplingcapacitance would become lower during the depression of the keycap 12.

It should be noted that it is not necessary for the pair of the firstand second sensor electrodes 100 a, 100 b to be disposed at the sameside of the insulating layer 101.

Sixth Embodiment

Reference is made to FIG. 10, which is a schematic sectional view of akey unit in an undepressed state according to a sixth embodiment of thepresent disclosure.

In the key unit 1F of the instant embodiment, the first and secondsensor electrodes 100 a, 100 b of the capacitance sensing circuit 100are disposed at the same membrane 102, but respectively disposed at twoopposite sides of the membrane 102. As shown in FIG. 10, the first andsecond sensor electrodes 100 a, 100 b do not overlap with each other ina direction (vertical direction) of motion of the keycap 12 so as toprevent the coupling between the finger F and the second sensorelectrode 100 b that is located at a lower position from beinginterfered by the first sensor electrode 100 a that is disposed at anhigher position.

In one embodiment, after the first and second electrodes 100 a, 100 bare formed on the membrane 102, the membrane 102 together with the firstand second sensor electrodes 100 a, 100 b formed thereon are connectedto the ground layer 103 by an adhesive layer 104. In another embodiment,the membrane 102 together with the first and second sensor electrodes100 a, 100 b formed thereon can be directly disposed on the ground layer103.

Furthermore, in the instant embodiment, the floating conductivestructure 14 is a conductive layer covering a portion of the elasticelement 11. Specifically, the conductive layer partially covers thesurfaces of the protrusion portion 111 and the supporting portion 112that faces toward the circuit board 10.

Seventh Embodiment

Reference is made to FIG. 11, which is a schematic sectional view of akey unit in an undepressed state according to a seventh embodiment ofthe present disclosure. The elements which are similar to or the same asthose shown in FIG. 10 are denoted by similar or the same referencenumerals, and will not be reiterated herein.

In the key unit 1G of the instant embodiment, the first and secondsensor electrodes 100 a, 100 b of the capacitance sensing circuit 100are respectively disposed at two different membranes 102. In oneembodiment, after the first and second electrodes 100 a, 100 b arerespectively formed on the two membrane 102, one of the membranes 102with the second sensor electrode 100 b formed thereon is connected tothe ground layer 103 by an adhesive layer 104 a, and the other membrane102 is connected to the one of the membranes with the second sensorelectrode 100 b formed thereon by another adhesive layer 104 b. That isto say, the first and second sensor electrodes 100 a, 100 b, which arerespectively formed at different membranes 102 and face toward eachother, are vertically spaced apart from each other by the anotheradhesive layer 104 b.

Eighth Embodiment

Reference is made to FIG. 12, which is a schematic sectional view of akey unit in an undepressed state according to an eighth embodiment ofthe present disclosure. The elements which are similar to or the same asthose shown in FIG. 11 are denoted by similar or the same referencenumerals, and will not be reiterated herein.

In the key unit 1H of the instant embodiment, the adhesive layer 104 bcan be omitted. That is to say, the membrane 102 with the second sensorelectrode 100 b disposed thereon can be directly disposed on the groundlayer 103.

Furthermore, only one adhesive layer 104 is used to connect one of themembranes 102 that is disposed with the first sensor electrode 100 a tothe other membrane 102 that is disposed with the second sensor electrode100 b.

Ninth Embodiment

Reference is made to FIG. 13 and FIG. 14, which are schematic sectionalviews of a key unit respectively in an undepressed state and in adepressed state according to the ninth embodiment of the presentdisclosure.

In the key unit 1I of the ninth embodiment, the floating conductivestructure 14 is a conductive layer that is disposed at the end of theprotrusion portion 111.

Furthermore, in the instant embodiment, the circuit board 10 has anopening 10H in alignment with the protrusion portion 111 in the verticaldirection. Specifically, the opening 10H of the circuit board 10 extendsfrom an upper surface of the circuit board 10 to the surface of theinsulating layer 101 that is formed with the capacitance sensing circuit100. The position of the opening 10H is offset from the positions of thefirst and second sensor electrodes 100 a, 100 b.

In the instant embodiment, the first and second sensor electrodes 100 a,100 b are exposed from a sidewall of the circuit board 10 that definesthe opening 10H. In another embodiment, the first and second sensorelectrodes 100 a, 100 b may not be exposed, and the present disclosureis not limited to the examples provided herein.

As shown in FIG. 13, when the keycap 12 is not depressed, the protrusionportion 111 of the elastic element 11 is located above the opening 10H.When the keycap 12 is depressed, as shown in FIG. 14, the protrusionportion 111 is pushed into the opening 10H without being in contact withthe pair of the first and second sensor electrodes 100 a, 100 b.

It should be noted that in the instant embodiment, it is not necessaryfor the protrusion portion 111 to be contact with the bottom of theopening 10H (or the surface of the insulating layer 101). To be morespecific, the coupling capacitance would be varied during the depressionof the keycap 12 since the floating conductive structure 14 formed atthe end of the protrusion portion 111 becomes closer and closer to thecapacitance sensing circuit 100 and alters the electric field.Accordingly, the processing circuit 13 can obtain the variation of thecoupling capacitance and determine the state of the keycap 12corresponding thereto.

Tenth Embodiment

Reference is made to FIG. 15 and FIG. 16, which are schematic sectionalviews of a key unit respectively in an undepressed state and in adepressed state according to the ninth embodiment of the presentdisclosure. One of the differences between the key unit 1J of the tenthembodiment and the key unit 1I of the ninth embodiment is that theprotrusion portion 111 of the instant embodiment extends into theopening 10H. As shown in FIG. 15, when the keycap 12 is not depressed,an ending portion of the protrusion portion 111 and the floatingconductive structure 14 formed thereon are located in an upper portionof the opening 10H of the circuit board 10.

However, the protrusion portion 111 and the floating conductivestructure 14 would be not in contact with the surface of the insulatinglayer 101 so as to reserve a space that allows the protrusion portion111 to move downwardly during the depression of the keycap 12.

As shown in FIG. 16, when the keycap 12 is pressed by a user with thefinger F, the protrusion portion 111 and the floating conductivestructure 14 formed thereon are forced to move from the upper portion tothe lower portion of the opening 10H, such that a distance between thefloating conductive structure 14 and the capacitance sensing circuit 100becomes shorter.

As such, the coupling capacitance between the pair of the first andsecond sensor electrodes 100 a, 100 b is varied. Accordingly, theprocessing circuit 13 can obtain the variation of the couplingcapacitance and determine the state of the keycap 12 correspondingthereto.

Furthermore, in the instant embodiment, the floating conductivestructure 14 that is formed on the protrusion portion 111 may be incontact with the surface of the insulating layer 101 after the keycap 12is depressed and reaches to its lowest extent. Moreover, the floatingconductive structure 14 and the capacitance sensing circuit 100 arelocated at the same level.

Eleventh Embodiment

Reference is made to FIG. 17, which is a schematic sectional view of akey unit in an undepressed state according to an eleventh embodiment ofthe present disclosure. The elements which are similar to or the same asthose shown in FIG. 15 are denoted by similar or the same referencenumerals, and will not be reiterated herein.

In the key unit 1K of the eleventh embodiment, the circuit board 10further includes a switch sensing circuit 105 for sensing pressingevents. The switch sensing circuit 105 is insulated from and disposedbelow the capacitance sensing circuit 100. That is to say, in theinstant embodiment, the switching sensing circuit 105, the membrane 102and the capacitance sensing circuit 100 are sequentially disposed on theinsulating layer 101, and the switch sensing circuit 105 and thecapacitance sensing circuit 100 are spaced apart from each other by themembrane 102.

Moreover, the switch sensing circuit 105 includes a first detectinglayer 105 a and a second detecting layer 105 b. The first detectinglayer 105 a and the second detecting layer 105 b are insulated from eachother and alternately arranged at the same insulating layer 101.

As shown in FIG. 17, a portion of the first detecting layer 105 a and aportion of the second detecting layer 105 b are spaced apart from eachother so as to define a contact point P1 therebetween. The contact pointP1 is in alignment with the protrusion portion 111 of the elasticelement 11 in the vertical direction.

The circuit board 10 also has the opening 10H. The opening 10H passesthrough a layer of the capacitance sensing circuit 100, but the opening10H does not pass through the switch sensing circuit 105. That is tosay, a portion of the first detecting layer 105 a, a portion of thesecond detecting layer 105 b, and the contact point P1 definedtherebetween are located at the bottom of the opening 10H.

Furthermore, the switch sensing circuit 105 of each key unit 1K can beelectrically connected to the processing circuit 13 to which thecapacitance sensing circuit 100 is electrically connected. That is tosay, the processing circuit 13 can receive switch signals transmitted bythe switch sensing circuit 105 so as to determine whether the keycap 12is depressed to its lowest extent or not. In another embodiment, theswitch sensing circuit 105 and the capacitance sensing circuit 100 canbe electrically connected to different processing circuits 13,respectively.

The key unit 1K further includes a flexible conductive film 15 disposedon the circuit board 10 and covering the opening 10H. The flexibleconductive film 15 is disposed above and insulated from the capacitancesensing circuit 100. Furthermore, since the opening 10H is below theprotrusion portion 111 of the elastic element 11, the flexibleconductive film 15 that covers the opening 10H is in alignment with theprotrusion portion 111. The flexible conductive film 15 can be made of aconductive and resilient material, such as a carbon film. In the instantembodiment, the floating conductive structure 14 can be omitted.

Reference is made to FIG. 17, FIG. 18 and FIG. 19, in which FIG. 18 is aschematic sectional view of the key unit located at a middle positionaccording to the eleventh embodiment of the present disclosure, and FIG.19 is a schematic sectional view of a key unit held in the depressedstate according to the eleventh embodiment of the present disclosure.

As shown in FIG. 18, during the depression of the keycap 12, theprotrusion portion 111 moves downwardly and forces the flexibleconductive film 15 to deform and become closer to the capacitancesensing circuit 100. That is, when the keycap 12 moves toward thecircuit board 10, the protrusion portion 111 forces the flexibleconductive film 15 to deform so that the flexible conductive film 15extends into the opening 10H.

Accordingly, the coupling capacitance would be changed, and theprocessing circuit 13 can obtain the variation of the couplingcapacitance so as to determine whether the keycap 12 is depressed.However, since the flexible conductive film 15 is not in contact withthe contact point P1 of the switch sensing circuit 105, the processingcircuit 13 does not receive any switch signal.

Reference is made to FIG. 19. When the keycap 12 is depressed to itslowest extent, the protrusion portion 111 moves to the bottom of theopening 10H, such that the flexible conductive film 15 extends into theopening 10H and is in contact with the contact point P1 below. As such,the switch sensing circuit 105 is closed, and the processing circuit 13can receive the switch signal corresponding to the keycap 12 anddetermine that the keycap 12 is depressed to its lowest extent.

Accordingly, in the instant embodiment, the processing circuit 13 canobtain both the variation of the coupling capacitance and the switchsignal so as to double check the state of the keycap 12, therebypreventing from the “phantom switch” problems. That is to say, in thepresent disclosure, the accuracy of the processing circuit 13 fordetermining the state of the keycap 12 can be improved.

Twelfth Embodiment

Reference is made to FIG. 20, which is a schematic sectional view of akey unit in an undepressed state according to a twelfth embodiment ofthe present disclosure. The elements which are similar to or the same asthose shown in FIG. 1 are denoted by similar or the same referencenumerals, and will not be reiterated herein.

In the instant embodiment, a key unit 1L further includes a supportingassembly 16. The supporting assembly 16 is disposed between the keycap12 and the circuit board 10, and the supporting assembly 16 allows thekeycap 12 to be moved between the non-depressed position and a depressedposition with respect to the circuit board 10.

Specifically, the supporting assembly 16 can be a scissors-shaped frame.It should be noted that in the instant embodiment, the elastic element11 is optional and can be omitted. That is to say, the elastic element11 can be replaced by the supporting assembly 16. As shown in FIG. 20,the supporting assembly 16 includes a first supporting frame 161 and asecond supporting frame 162. In the instant embodiment, the firstsupporting frame 161 may surround the second supporting frame 162. Eachof the first supporting frame 161 and the second supporting frame 162 isinclined relative to the circuit board 10.

The first supporting frame 161 and the second supporting frame 162 areboth inclined relative to the circuit board 10 and respectively extendin different directions. The circuit board 10 of the instant embodimentincludes two chutes (not shown in FIG. 20), and the first supportingframe 161 has an end portion that is slidably coupled to the chutes.Furthermore, the circuit board 10 may include two pivoting supports (notshown in FIG. 20), and an end portion of the second supporting frame 162is coupled to the pivoting supports. Similarly, the keycap 12 mayinclude two chutes and two pivoting supports. The first supporting frame161 has another end portion that is coupled to the pivoting supports ofthe keycap 12, and the second supporting frame 162 has another endportion that is coupled to the chutes of the keycap 12.

The supporting assembly 16 can be made of, but not limited to, aconductive material, an insulating material, or a composite material.For example, the supporting assembly 16 can be made of a metal-platedplastic material.

Specifically, in the instant embodiment, the key unit 1L furtherincludes a floating conductive structure 14, and the floating conductivestructure 14 is disposed on the supporting assembly 16. It should benoted that an orthogonal projection of the floating conductive structure14 on the circuit board 10 overlaps with the first sensor electrodes 100a and the second sensor electrodes 100 b.

Referring to FIG. 21, when the keycap 12 is pressed, an angle betweenthe first supporting frame 161 and the second supporting frame 162 andan angle between the circuit board 10 and any one of the firstsupporting frame 161 and the second supporting frame 162 are altered, sothat the keycap 12 can be moved downwardly. Meanwhile, the floatingconductive structure 14 becomes closer to the capacitance sensingcircuit 11 so that the electric field between the pair of the first andsecond sensor electrodes 100 a, 100 b is altered, thereby changing thecoupling capacitance. That is to say, the floating conductive structure14 is moved with a motion of the keycap 12, such that the couplingcapacitance is varied. It should be noted that by disposing the floatingconductive structure 14, the electric field between the pair of thefirst and second sensor electrodes 100 a, 100 b is still altered eventhough the keycap 12 is depressed by a nonconductive object (such as aplastic stylus).

Furthermore, in the instant embodiment, the floating conductivestructure 14 is a conductive layer that completely covers an outersurface of each of the first supporting frame 161 and the secondsupporting frame 162. Specifically, the floating conductive structure 14can be an electrodeposition layer which can be made of copper, stainlesssteel, or a combination thereof. The floating conductive structure 14 isneither connected to any electric power source through a wire norreceived with a driving current.

As shown in FIG. 20 and FIG. 21, the key unit 1L further includes aprocessing circuit 13 that is electrically connected to the pair of thefirst and second sensor electrodes 100 a, 100 b to detect the couplingcapacitance between the pair of the first and second sensor electrodes100 a, 100 b and to determine whether the keycap 12 is touched ordepressed according to the coupling capacitance.

Specifically, the capacitance sensing circuit 100 can transmit acoupling capacitance signal, such as a current value or a voltage value,to the processing circuit 13, so that the processing circuit 13 canmeasure the variation of the coupling capacitance and determine whetherthe variation of the coupling capacitance is greater than a firstthreshold value or not. When the variation of the coupling capacitanceis greater than a first threshold value, the keycap 12 is determined tobe touched.

In the instant embodiment, when the keycap 12 is touched by a finger Fof a user, the variation of the coupling capacitance is negative. Whenan absolute value of the variation of the coupling capacitance isgreater than the first threshold value, the processing circuit 13 candetermine that the keycap 12 is touched, but is not pressed.

Furthermore, when the keycap 12 is pressed by the finger F, since alargest vertical distance between the floating conductive structure 14and the pair of the first and second sensor electrodes 100 a, 100 b isreduced, the variation of the coupling capacitance is positive. When thevariation of the coupling capacitance is greater than a second thresholdvalue, the processing circuit 13 determines that the keycap 12 ispressed.

It is worth mentioning that the supporting assembly 16 can be made ofconductive material. When the supporting assembly 16 is made ofconductive material, the floating conductive structure 14 is optionaland can be omitted. In that case, the supporting assembly 16 made ofconductive material is neither connected to any electric power sourcethrough a wire nor received with a driving current.

Thirteenth Embodiment

Reference is made to FIG. 22, which is a schematic sectional view of akey unit in an undepressed state according to a thirteenth embodiment ofthe present disclosure. The elements which are similar to or the same asthose shown in FIG. 20 are denoted by similar or the same referencenumerals, and will not be reiterated herein.

In the instant embodiment, the floating conductive structure 14 is aconductive layer that covers a part of supporting assembly 16. That isto say, the floating conductive structure 14 covers one of the firstsupporting frame 161 and the second supporting frame 162. As shown inFIG. 0.22, the conductive layer (or the floating conductive structure14) only covers an upper part of the first supporting frame 161.Accordingly, the floating conductive structure 14 is farther away fromthe circuit board 10 and closer to the keycap 12. It should be notedthat the orthogonal projection of the floating conductive structure 14still overlaps both the first sensor electrode 100 a and the secondsensor electrode 100 b. Referring to FIG. 22 and FIG. 23, when thekeycap 12 are respectively in the non-depressed position and thedepressed position, a variation of the largest vertical distance betweenthe floating conductive structure 14 and the circuit board 10 can bemaximized, so that a sensitivity of the key unit 1M can be maintained ata certain level.

However, the present disclosure is not limited to the aforementionedembodiment. In another embodiment, the conductive layer (or the floatingconductive structure 14) may only cover an upper part of the secondsupporting frame 162.

Fourteenth Embodiment

Reference is made to FIG. 24, which is a schematic sectional view of akey unit in an undepressed state according to a fourteenth embodiment ofthe present disclosure. The elements which are similar to or the same asthose shown in FIG. 23 are denoted by similar or the same referencenumerals, and will not be reiterated herein.

In the key unit 1N of the instant embodiment, the floating conductivestructure 14 includes a first conductive layer 14 a and a secondconductive layer 14 b. The first conductive 14 a layer covers the firstsupporting frame 161, and is located at an upper part of the firstsupporting frame 161. That is to say, the first conductive layer 14 a isfarther away from the circuit board 10 and closer to the keycap 12.

Similarly, the second conductive layer 14 b covers the second supportingframe 162 and is located at an upper part of the second supporting frame162. The second conductive layer 14 b is closer to the keycap 12. In theinstant embodiment, orthogonal projections of the first conductive layer14 a and the second conductive layer 14 b on the circuit board 10 do notoverlap with each other. However, each of the orthogonal projections ofthe first conductive layer 14 a and the second conductive layer 14 b onthe circuit board 10 partially overlaps with the first sensor electrode100 a or the second sensor electrode 100 b.

Referring to FIG. 25, when the keycap 12 is pressed, a largest verticaldistance between the first conductive layer 14 a and the pair of thefirst and second sensor electrodes 100 a, 100 b and a largest verticaldistance between the second conductive layer 14 b and the pair of thefirst and second sensor electrodes 100 a are both reduced, such that thecoupling capacitance is changed. As such, the processing circuit 13 candetermine whether or not the keycap 12 is pressed according to thevariation of the coupling capacitance.

In one embodiment, each of the first conductive layer 14 a and thesecond conductive layer 14 b is an electrodeposited layer which can bemade of copper, stainless steel, or a combination thereof. However, thematerial of the first conductive layer 14 a and the second conductivelayer 14 b of the present disclosure is not limited to the examplesprovided herein.

Fifteenth Embodiment

Reference is made to FIG. 26, which is a schematic sectional view of akey unit in an undepressed state according to a fifteenth embodiment ofthe present disclosure. The elements which are similar to or the same asthose shown in FIG. 20 are denoted by similar or the same referencenumerals, and will not be reiterated herein.

In the instant embodiment, the key unit 1P of the instant embodimentfurther includes a balance frame 17, and the balance frame 17 is made ofconductive material. When the key unit 1P has a longer length, such as“space” key or “shift” key, the balance frame 17 is disposed under thekeycap 12 to balance a force exerted on one end of the keycap 12. Inthis way, the key unit 1P can be levelly depressed downwardly even whenthe force is exerted on one end of the keycap 12.

The balance frame 17 may be disposed to surround the supporting assembly16. That is to say, the balance frame 17 is disposed at an outside ofthe supporting assembly 16, and the balance frame 17 is separate fromthe supporting assembly 16.

It should be noted that at least one of the supporting assembly 16 andthe balance frame 17 is electrically conductive and has an orthogonalprojection on the circuit board 10 overlapping with the capacitancesensing circuit 100. In the instant embodiment, the balance frame 17 ismade of conductive material. Furthermore, an orthogonal projection ofthe balance frame 17 on the circuit board 10 overlaps with the pair offirst and second sensor electrodes 100 a, 100 b. In this way, a largestvertical distance between the balance frame 17 and the pair of the firstand second sensor electrodes 100 a, 100 b is changed with the movementof the keycap 12. When the keycap 12 is moved downwardly, the couplingcapacitance between the pair of the first and second sensor electrodes100 a, 100 b is also changed. Accordingly, in the instant embodiment,the floating conductive structure 14 is optional and can be omitted.

Reference is made to FIG. 27 and FIG. 27. FIG. 28 is a top view of akeyboard according to an embodiment of the present disclosure, and FIG.27 is a block diagram of a keyboard according to an embodiment of thepresent disclosure.

The keyboard Z is shown as a stand-alone keyboard rather than oneintegrated with a computer. However, in another embodiment, the keyboardZ can be integrated within the housing or chassis of the computer orother device components, such as a mobile phone, electronic book,computer, laptop, tablet computer, stand-alone keyboard, input device,an accessory (such a tablet case with a build-in keyboard), monitor,electronic kiosk, gaming device, automated teller machine (ATM), vehicledashboard, control panel, medical workstation, and industrialworkstation.

The keyboard Z can be electrically coupled to or integrated in acomputer system to serve as a user interface so that a user can input acommand. Moreover, the keyboard Z can also include a touchpad and otherinput mechanisms, which are not shown in FIG. 20, but the presentdisclosure is not limited to the example provided herein.

As shown in FIG. 20, the keyboard Z includes a housing Z1 and aplurality of key units Z2 that are housed in the housing Z1 and arrangedin an array. Specifically, the housing Z1 may include a bottom board anda top plate to define an accommodating space.

The key unit Z2 can be any one of the key units 1A-1N, 1P that arerespectively described in the first to eleventh embodiments. The keyunits Z2 can be accommodated in accommodating space defined by thehousing Z1. An outer surface of the keycap of each of the key units Z2is exposed from the housing Z1 for operational convenience. It should benoted that in one embodiment of the present disclosure, the keyboard Zis mechanical keyboard capable of detecting coupling capacitancesignals. In one embodiment, the keyboard Z can be a touch sensitivemechanical keyboard for detecting both touching and depression events.

As shown in FIG. 21, the keyboard Z further includes a processor Z3 thatis electrically connected to the processing circuit 13 to receive stateinformation of each of the key units Z2. In one embodiment, theprocessor Z3 can be a programmable logic controller, a logic circuit, amicroprocessor, or any combination thereof. In this embodiment, theprocessor Z3 is electrically connected to the processing circuit 13;however, in another embodiment, the processing circuit 13 can beincorporated into the processor Z3. It should be noted that only one ofthe key units Z2 is exemplarily shown in FIG. 21. Furthermore, the keyunit Z2 having the same functions as those of the key unit 1K shown inFIG. 17 is only taken as an example in the instant embodiment, and thepresent disclosure is not limited thereto. In another embodiment, theswitch sensing circuit 105 may be omitted.

The processing circuit 13 receives coupling capacitance signalstransmitted from the capacitance sensing circuit 100 and switch signalstransmitted from the switch sensing circuit 105 so as to determine thestate of the keycap 12. For example, the processing circuit 13 candetermine whether the keycap 12 of the key unit Z2 is touched or notaccording to the coupling capacitance signals. Moreover, the processingcircuit 13 can determine whether the keycap 12 of the key unit Z2 isdepressed or not according to either the coupling capacitance signals orthe switch signals.

After the processing circuit 13 determines the state of the keycap 12,the processing circuit 13 transmits state information corresponding tothe key unit Z2 to the processor Z3, in which the state information mayinclude an address of the key unit Z2 and a state signal of the key unitZ2. The state signals may be a non-contact signal, a touched signal or adepressed signal. In one embodiment, the state information of every oneof the key units Z2 can be transmitted by the same processing circuit 13to the processor Z3.

Specifically, when the key unit Z2 is in a touched state, i.e., the keyunit Z2 is touched but not depressed, the processing circuit 13transmits the address and the touched signal, both of which correspondto the touched key unit Z2, to the processor Z3. When the key unit Z2 isin a depressed state, the processing circuit 13 transmits the addressand the depressed signal, both of which correspond to the depressed keyunit Z2, to the processor Z3.

In one embodiment, the processor Z3 may be electrically connected to acontrol chip of a host. The processor Z3 transmits the state informationcorresponding to a certain key unit to the control chip so that thecontrol chip can execute a program corresponding to the stateinformation of a certain key unit. Reference is made to FIG. 27 inconjunction with FIG. 28. For example, if the key unit Z2 having acharacter “A” (the “A” key unit) is touched but not depressed, theprocessing circuit 13 will transmit the state information correspondingto the “A” key unit to the processor Z3. If two or three key units Z2,such as the key units Z2 respectively having characters “A” and “W” (the“A” key unit and the “W” key unit), are touched substantially at thesame time, the processing circuit 13 will transmit the state informationcorresponding to the “A” key unit and the state informationcorresponding to the “W” key unit to the processor Z3.

Furthermore, in one embodiment, a user can input a command through thekeyboard Z by performing a gesture or a movement with an object on thekey units Z2. The gesture or the movement may include continuouslytouching, continuously pressing, or a combination of continuouslytouching and pressing a series of key units to form a particular trace(such as a clock-wise circle), or holding down on one of the key unitswhile performing the foregoing actions, but the present disclosure isnot limited thereto. It should be noted that the processor Z3.

In one embodiment, a gesture or a movement may correspond to a commandthat is used to control cursor movement displayed on a screen. Forexample, a user can control the cursor to move along a direction bycontinuously touching the “D” key unit, the “S” key, and the “A” keyunit or by continuously touching the “R” key unit, the “E” key, and the“W” key unit in a first sequence along a first direction D1. Similarly,the user can control the cursor to move along another direction bycontinuously touching the “D” key unit, the “S” key, and the “A” keyunit in a second sequence (i.e., in the reverse sequence to the firstsequence) along a second direction D2. Moreover, the cursor can becontrolled to move along another direction by continuously touching the“X” key unit, the “S” key, and the “W” key unit in a third sequencealong a third direction D3 or in a fourth sequence along a fourthdirection D4. That is to say, by continuously touching a series of keyunits in different directions, the user can control the cursor displayedon the screen to move up, down, left, or right.

In one embodiment, a user can input a command by touching and pressingthe “D” key unit, the “S” key, and the “A” key unit. For example, theuser can touch the “D” key unit, and then sequentially press the “S” keyunit and the “A” key unit so as to input the command corresponding tothe movement.

Specifically, when a user touches or/and presses a series of key unitsZ2 (for example, the “A” key unit, the “S” key unit, and the “D” keyunit) in a predetermined sequence, the processing circuit 13 transmitsthe state information respectively corresponding to the series of keyunits Z2 to the processor Z3.

In another embodiment, a user can touch a number of the key units Z2 toform a particular trace while the user is holding down on one of the keyunits Z2 so as to input a command. That is to say, a gesture or amovement can be touching a number of key units Z2 (for example, the “W”key unit, the “E” key unit, the “D” key unit, the “X” key unit, the “Z”key unit, and the “A” key unit) to form a particular trace T1 (such as aclock-wise circle) while pressing and holding down on another one of thekey units Z2 (such as the “Ctrl” key or the “Shift” key).

Thereafter, according to the state information, the processor Z3 canidentify the gesture performed by the user, and transmits an operatingsignal, which corresponds to the gesture, to the control chip of thehost that is electrically connected to the processor Z3. The controlchip can executes a specific program according to the operating signal.However, in another embodiment, the step of identifying the gesture ofthe user can be directly performed by the control chip of the host thatis electrically connected to the processor Z3.

Furthermore, the keyboard Z or a host that is electrically connectedthereto further includes a memory (not shown in FIG. 28). The memory iselectrically connected to the processor Z3 or the control chip of thehost, and stores a plurality of operating signals respectivelycorresponding to different gestures or movements, and stores a pluralityof programs respectively corresponding to different operating signals.

For example, the memory stores at least a first program corresponding toa first operating signal and a first gesture and a second programcorresponding to the second operating signal and a second gesture. Theprocessor Z3 determines whether the gesture performed by a user is thefirst gesture, the second gesture, or neither.

When the processor Z3 determines that the gesture performed by a user isthe first gesture, the processor Z3 transmits the first operating signalto the control chip, such that the control chip executes the firstprogram according to the first operating signal. Similarly, when theprocessor Z3 determines that the gesture performed by a user is thesecond gesture, the control chip executes the second program accordingto the second operating signal transmitted from the processor Z3.

For example, the first gesture can be touching the series of key unitsin the first sequence, and the second gesture can be pressing the seriesof key units Z2 in the second sequence.

However, in another embodiment, the gesture or the movement may be thattouching a series of the key units in a clockwise direction or in acounterclockwise direction, and the present disclosure is not limited inthis aspect.

In conclusion, one of the advantages of the present disclosure is thatin the key units 1A-1N, 1P and the keyboard Z using the same providedherein, by the technical features of a circuit board 10 including acapacitance sensing circuit 100 embedded therein, the capacitancesensing circuit 100 including a pair of sensor electrodes 100 a, 100 bwhich are spaced apart from each other, a floating conductive structurebeing disposed on the supporting assembly, in which an orthogonalprojection of the floating conductive structure on the circuit boardoverlaps with the pair of sensor electrodes and a processing circuit 13being electrically connected to the pair of sensor electrodes 100 a, 100b to obtain a variation of a coupling capacitance between the pair ofsensor electrodes 100 a, 100 b and to determine whether the keycap 12 istouched or depressed according to the variation of coupling capacitance,the accuracy of detection can be improved and the “phantom switch”problems can be prevented even if more than two key units Z2 of thekeyboard Z are depressed at the same time.

Furthermore, in one embodiment, the keyboard Z can determine whether aseries of key units Z2 are continuously touched in a predeterminedsequence according to the variations of the coupling capacitancerespectively corresponding thereto so that a user can input a specificcommand by performing a specific gesture or movement.

The foregoing description of the exemplary embodiments of the disclosurehas been presented only for the purposes of illustration and descriptionand is not intended to be exhaustive or to limit the disclosure to theprecise forms disclosed. Many modifications and variations are possiblein light of the above teaching.

The embodiments were chosen and described in order to explain theprinciples of the disclosure and their practical application so as toenable others skilled in the art to utilize the disclosure and variousembodiments and with various modifications as are suited to theparticular use contemplated. Alternative embodiments will becomeapparent to those skilled in the art to which the present disclosurepertains without departing from its spirit and scope.

What is claimed is:
 1. A key unit comprising: a circuit board includinga capacitance sensing circuit embedded therein; a supporting assemblydisposed on the circuit board; a keycap moveably disposed above andspaced apart from the circuit board, wherein the supporting assembly isdisposed between the keycap and the circuit board and allows the keycapto be moved between a non-depressed position and a depressed positionwith respect to the circuit board; and a floating conductive structuredisposed on the supporting assembly, wherein an orthogonal projection ofthe floating conductive structure on the circuit board overlaps with thecapacitance sensing circuit.
 2. The key unit according to claim 1,wherein the capacitance sensing circuit includes a pair of sensorelectrodes which are spaced apart from each other, and the orthogonalprojection of the floating conductive structure on the circuit boardoverlaps with the pair of sensor electrodes.
 3. The key unit accordingto claim 1, wherein the supporting assembly includes a first supportingframe and a second supporting frame, and the floating conductive layeris a conductive layer covering at least one of the first supportingframe and the second supporting frame.
 4. The key unit according toclaim 1, wherein the supporting assembly includes a first supportingframe and a second supporting frame, and the floating conductivestructure is a conductive layer that covers an upper part of at leastone of the first supporting frame and the second supporting frame. 5.The key unit according to claim 1, wherein the supporting assemblyincludes a first supporting frame and a second supporting frame, and thefloating conductive structure includes: a first conductive layerpartially covering the first supporting frame, wherein the firstconductive layer is located at an upper part of the first supportingframe; and a second conductive layer partially covering the secondsupporting frame, wherein the second conductive layer is located at anupper part of the second supporting frame; wherein orthogonalprojections of the first conductive layer and the second conductivelayer on the circuit board do not overlap with each other.
 6. The keyunit according to claim 1, further including a processing circuitelectrically connected to the capacitance sensing circuit. to obtain avariation of a coupling capacitance and to determine whether the keycapis touched or depressed according to a variation of couplingcapacitance; in response to the variation of the coupling capacitance isgreater than a first threshold value and less than a second thresholdvalue, the keycap is determined to be touched; and in response to thevariation of the coupling capacitance is greater than the secondthreshold value, the keycap is determined to be depressed.
 7. The keyunit according to claim 1, further includes an elastic element disposedon the circuit board, wherein the elastic element includes a connectionportion and a protrusion portion, the connection portion connects to thekeycap, and the protrusion portion extends from the connection portiontoward the circuit board; and when the keycap is in a non-depressedposition, the protrusion portion is spaced apart from the circuit board.8. The key unit according to claim 7, wherein the capacitance sensingcircuit includes a pair of sensor electrodes which are spaced apart fromeach other, the circuit board has an opening that extends from an uppersurface of the circuit board to a position between the pair of thesensor electrodes and is in alignment with the protrusion portion; whenthe keycap moves toward the circuit board, the protrusion portion ispushed into the opening without being in contact with the pair of thesensor electrodes.
 9. The key unit according to claim 7, wherein thecircuit board further includes: a switch sensing circuit having at leasta contact point that is in alignment with the protrusion portion,wherein the capacitance sensing circuit is disposed above and insulatedfrom the switch sensing circuit, the circuit board has an opening inalignment with the contact point, and the opening passes through thecapacitance sensing circuit, and does not pass through the switchsensing circuit.
 10. The key unit according to claim 9, furtherincluding a flexible conductive film disposed above and insulated fromthe capacitance sensing circuit, wherein the flexible conductive filmcovers the opening; when the keycap moves toward the circuit board, theprotrusion portion forces the flexible conductive film to deform so thatthe flexible conductive film extends into the opening to contact thecontact point below.
 11. A key unit comprising: a circuit boardincluding a capacitance sensing circuit embedded therein; a supportingassembly disposed on the circuit board; a keycap moveably disposed aboveand spaced apart from the circuit board, wherein the supporting assemblyis disposed between the keycap and the circuit board and allows thekeycap to be moved between a non-depressed position and a depressedposition with respect to the circuit board; and a balance frame disposedbetween the keycap and circuit board and surrounding the supportingassembly; wherein at least one of the balance frame and the supportingassembly is made of conductive material and has an orthogonal projectionon the circuit board overlapping with the capacitance sensing circuit.12. The key unit according to claim 11, wherein the capacitance sensingcircuit includes a pair of sensor electrodes which are spaced apart fromeach other, and the orthogonal projection of the balance frame on thecircuit board overlaps with the pair of sensor electrodes.
 13. Akeyboard comprising: a plurality of key units, wherein each of the keyunits includes: a circuit board including a capacitance sensing circuitembedded therein; a supporting assembly disposed on the circuit board; akeycap moveably disposed above and spaced apart from the circuit board,wherein the supporting assembly is disposed between the keycap and thecircuit board and allows the keycap to be moved between a non-depressedposition and a depressed position with respect to the circuit board; anda floating conductive structure disposed on the supporting assembly,wherein an orthogonal projection of the floating conductive structure onthe circuit board overlaps with the capacitance sensing circuit; and aprocessing circuit electrically connected to the capacitance sensingcircuit of each of the key units to obtain a variation of a couplingcapacitance and to determine whether the keycap is touched or depressedaccording to the variation of coupling capacitance; when the variationof the coupling capacitance is greater than a first threshold value andless than a second threshold value, the keycap is determined to betouched; and when the variation of the coupling capacitance is greaterthan the second threshold value, the keycap is determined to bedepressed.
 14. The keyboard according to claim 13, wherein thecapacitance sensing circuit of each of the key units includes a pair ofsensor electrodes which are spaced apart from each other andelectrically connected to the processing circuit, and the orthogonalprojection of the floating conductive structure on the circuit boardoverlaps with the pair of sensor electrodes.
 15. The keyboard accordingto claim 13, wherein the supporting assembly includes a first supportingframe and a second supporting frame, and the floating conductive layeris a conductive layer completely covering at least one of the firstsupporting frame and the second supporting frame.
 16. The keyboardaccording to claim 13, wherein the supporting assembly includes a firstsupporting frame and a second supporting frame, and the floatingconductive structure is a conductive layer that covers an upper part ofat least one of the first supporting frame and the second supportingframe.
 17. The keyboard according to claim 13, wherein the supportingassembly includes a first supporting frame and a second supportingframe, and the floating conductive structure includes: a firstconductive layer partially covering the first supporting frame, whereinthe first conductive layer is located at an upper part of the firstsupporting frame; and a second conductive layer partially covering thesecond supporting frame, wherein the second conductive layer is locatedat an upper part of the second supporting frame; wherein both oforthogonal projections of the first conductive layer and the secondconductive layer on the circuit board partially overlap with thecapacitance sensing circuit.
 18. The keyboard according to claim 13,further includes an elastic element disposed on the circuit board,wherein the elastic element includes a connection portion and aprotrusion portion, the connection portion connects to the keycap, andthe protrusion portion extends from the connection portion toward thecircuit board; and when the keycap is in a non-depressed position, theprotrusion portion is spaced apart from the circuit board.
 19. Thekeyboard according to claim 18, wherein the capacitance sensing circuitincludes a pair of sensor electrodes which are spaced apart from eachother, the circuit board has an opening that extends from an uppersurface of the circuit board to a position between the pair of thesensor electrodes and is in alignment with the protrusion portion; whenthe keycap moves toward the circuit board, the protrusion portion ispushed into the opening without being in contact with the pair of thesensor electrodes.
 20. The keyboard according to claim 18, wherein thecircuit board further includes: a switch sensing circuit having at leasta contact point that is in alignment with the protrusion portion of theelastic element, wherein the capacitance sensing circuit is disposedabove and insulated from the switch sensing circuit, the circuit boardhas an opening in alignment with the contact point, and the openingpasses through the capacitance sensing circuit, and does not passthrough the switch sensing circuit.
 21. The keyboard according to claim20, further including a flexible conductive film disposed above andinsulated from the capacitance sensing circuit, wherein the flexibleconductive film covers the opening; when the keycap moves toward thecircuit board, the protrusion portion forces the flexible conductivefilm to deform so that the flexible conductive film extends into theopening to contact the contact point below.
 22. The keyboard accordingto claim 13, further includes a processor electrically connected to theprocessing circuit, wherein the processor determines whether a series ofkey units are touched or pressed continuously in a predeterminedsequence according to the variations of the coupling capacitancerespectively corresponding thereto.
 23. The keyboard according to claim13, further includes a processor electrically connected to theprocessing circuit and a memory electrically connected to the processor,wherein the memory stores a first program corresponding to a firstgesture, and the processor determines whether a gesture performed by auser is the first gesture or not; wherein the first gesture is touchinga number of key units to form a particular trace while pressing andholding down on another one of the key units.